Inlay and bridge casting machine.



U ITED STATES PATENT OFFICE.-

ASA r. eoeswELI or KI RiWIN, KANSAS.

- INLAY AND BRIDGE CASTING MACHINE.

l 1 4 ,97 Specification of Letters Patent. t t d 10, 1912 i IApplication filed April 3, 1911. Serial No. 618,708.

.- cam-Toad whom it may concern:

Be it known that I, Am F. Coeswnnt, a citizen of the UnitedStates,residing at- Kirwin, in the county of Phillips and State of Kansas, haveinvented certain new and useful Improvements in Inlay'and Bridge CastingMachines, of which the following .isa specification,

This invention relates to improvements in 10 casting .machines, for usein the practice of dentistry, and my objectis to 'produce a simple,inexpensive machine of this character whereby perfect, sharp-edgedinlays, crowns, bridges etc., can be produced at a small expenditure oftime and labor.

he present invention relates more particularly to a novel crucibleand-anovel hopper therefor, the latter being provided chiefly to savethe time and labor now re- 2 0 quired in forming the usual hopper in theinvestment surrounding the wax impression.

The novel feature of the crucible resides more particularly in theprovision of means to prevent any passage of air between the 26 innerwalls of said crucible and the investment, to the end that suctionapplied tothe latter is concentrated to the region of the' :sprue-gateand the cavity. left in the investment by the wax impression. Thus a 30vacuum may be formed within the cavity and when the molten metal to formthe cast flows into said cavity through the sprite-gate, a perfect castin produced, as the metal being unopposed by airpressure,

flows into all of, the interstices of the cavity.

-In order that the. invention may be fully understood, reference willnow be made to the accompanying drawing, in which:

40 Figure 1 shows a vertical sectional view of the machine assembled foruse. Fig. .3 is a detail perspective view of the hopper forming part ofthe invention. Fig. 3 is a plan view of the crucible. Fig. at is avertical section of the crucible. and drawing the air from said cavityIn carrying out the invention, I employ a through cup 4. stem 5, duct.53, pipe (3, and

; couumrativcly heavy base I. having a centube 7. As the top '10 of thecrucible is nontral boss 2, with an L-shaped duct- 3 leading porous andthe hopper 19 is substantially to the top and one side of said boss.nonporous. air cannot pass through .the 105 4 designates a conical cupsupported by a. porous iuvcstu'icnt. except in the region contubularstem 5, the lower (breaded end of taining the cavity -and the gate,conse- \\'hich is screwed into the. upper portion of qucntly the vacuumproduced in the cavity.

the base and connnuuicates with the-vertical aided by the force ofgravity. will suck the leg of duct 3. metal from tbe hoppcr. downthrough the 110 (5 designates a horizontal pipe extending gate and intothe cavity, producing a perthrough one side of the base and conununifeeteast.

[eating with the horizontal leg of duct 3,

said pipe bcing provided at its outer end with a flexible. tube 7 havinga mouthpiece 8.

9 designates a conical crucible adapted to fit snugly into the upperportion of cup 4 and provided with a top portion 10, sloping downward toa central opening 11.

' 12 designates a conical hopper adapted to fit snugly upon top 10 ofthe crucible, and provided with a circular boss 13 to fit into opening11, said boss having a central sprue-hole 14 to receive the sprue A of awax impression B. Hopper 12 is composed, preferably of fire-clay orother suitablematerial which will withstand a high temperature withoutcracking, and which has no aflinity for molten metal, so that the samewill not adhere thereto.

In practice the crucible 9 is taken from cup 4, and the hopper 12 isplaced in position thereon. The crucible and hopper are then invertedand placed upon a smooth sur face, after which the wax impression B and3 sprue A are placed within the upturned crucible, the spruc A passingthrough hole 14, in the hopper, so that the same will support the sprueand the wax impression in upright position. The length of the sprue 35determines the location of the wax impressi'on B within the investmentC, which is now poured into the upturned crucible until the same isfilled therewith. After the investment becomes set, the crucible and thehopper are turned right side up and the sprne is removed, after whichthe crucible is subjected to sufficient heat to consume the waximpression, which leaves a cavity wit iin the investment, said cavitycommunicating with a gate left by the sprue. Metal to form the cast isnow placed in the hopper and melted, and when in a molten state, avacuum is created in the cavity, by applying the mouth to themouth-piece 8 a .ters Patent, is:

1. In a machine of the character described,- 15 a crucible, hav ng anintegral top thereon sloping downward to a central opening, and

a hopper adapted to snugly fit said top and provided with a centralopening.

2. In a machineof the type described a crucible formed w th an integraltop that 20 slopes downward to a central opening, and aconical hopperthat snugly'seat s on said f L01) and is formed with a central boss thatprojects down into the opening in the'crucible top and has a sprue-hole.25

In testimony whereof I aflix my signature, in the presence of twowitnesses.

ASA F. COGSWELL.

Witnesses:

F. G FISCI-IER, E. O. LILLIAN.

